1. Field
The following description relates to a resonator package and a method of manufacturing the same.
2. Description of Related Art
Due to the rapid development of mobile communications devices, the demand for subminiature filters, oscillators, and the like, has recently increased. To implement subminiature filters, oscillators, and the like, a bulk acoustic wave (BAW) resonator may be used.
BAW resonators are often used because BAW resonators may be mass-produced at a low price and may be subminiaturized. Further, BAW resonators can be used to obtain an excellent quality factor (Q factor), a main property of filters, and may be used in a micro-frequency band.
In configuring a filter with a BAW resonator, a capacitor structure is often included in a chip circuit.
A BAW resonator generally includes a lower electrode, a piezoelectric layer, and an upper electrode, and the capacitor includes a lower electrode, a dielectric layer, and an upper electrode. In this case, in order to simplify the manufacturing process and to reduce the material cost, the upper electrode of the resonator and the lower electrode of the capacitor are manufactured from the same material during the same process.
A structure of an existing resonator package described above will be described on the basis of the capacitor. Referring to FIGS. 1 through 4E, a resonator package includes an upper electrode 10′, a lower electrode 20′, a dielectric layer 30′, a piezoelectric layer 40′, and an insulating layer 50′. This structure is explicitly illustrated in FIG. 4E.
However, the lower electrode 20′ deposited on the piezoelectric layer 40′ of the resonator often uses a metal such as ruthenium (Ru) in order to secure crystallinity of the piezoelectric layer 40′. Patterning of the ruthenium (Ru) metal may be often performed via a dry etching using a hardmask HM such as an oxide.
In this case, because the lower electrode 20′ of the capacitor is patterned with a dry etching process using the hardmask HM, a reverse slope (RS) is easily generated on a short side of the lower electrode 20′. That is, because a gas G2 for etching the lower electrode 20′ may not etch the hardmask HM, an upper end portion of the lower electrode 20′ adjacent to the hardmask HM may not be etched and only a lower end portion of the lower electrode 20′ may be etched, such that a reverse slope (RS) is formed by the lower end portion being etched to a greater degree.
As a result, because coverage of the dielectric layer 30′ formed on an upper surface of the lower electrode 20′ of the capacitor may fail. Thus, a short circuit may occur between the upper electrode 10′, and the lower electrode 20′ of the upper electrode 10′ may fail.